Abstract: The reader is shown how to perform calculations for five problems. The first involves Citrolith tablets and shows how to calculate the quantity of potassium and sodium in each tablet and the quantity of potassium and sodium a patient would receive daily if taking the maximum recommended dose. The second involves an ointment that contains 0.5% mupirocin for a patient that now needs a strength of 1%. The reader is shown how to calculate the quantity of Bactroban ointment containing 2% mupirocin that should be added to the compounded ointment to raise the concentration to 1% and the final concentration of betamethasone valerate after adding the Bactroban ointment. The third shows how to calculate the quantity of nystatin that would be needed to prepare a batch of tablets of nystatin, each containing 500,000 units of nystatin. The fourth shows how to calculate the quantity of water that should be added to a vial containing 1.5 g of cefuroxime for injection to produce a concentration that is different from that given on the vial. The fifth shows how to calculate the quantity of paclitaxel that should be given to a patient of a certain height and weight, for treatment of breast cancer.